Vitamin B12 deficiency in captive monkeys and its effect on the nervous system and the blood.

Monkeys fed vegetarian diets develop neurological and haematological abnormalities; paralysis can occur though the neural lesions (cerebral degeneration, posterior and lateral column degeneration of the spinal cord, segmental and wallerian degeneration of the peripheral nerves) are usually not evident during life. It is clearly important that the diet given to captive animals should contain an adequate amount of vitamin B12, and that newly captive monkeys should not be used for research purposes unless shown to have normal serum levels of the vitamin.